The present invention relates to a flight plan preparing method and a flying vehicle guiding system for executing an autonomous flight of a small type unmanned air vehicle (UAV: Unmanned Air Vehicle).
In recent years, with a progress of a UAV (Unmanned Air Vehicle), various types of apparatuses are installed on the UAV and the UAV is flown by remotely controlling or by autonomously flying and works as required are carried out. For instance, a camera for photogrammetry and a scanner are installed on the UAV, and a measurement is performed downward from above the sky or the measurement is performed at a place where no operator can enter. And, for a positional measurement of the UAV itself, a GPS (Global Positioning System) is installed on the UAV, and a position of the UAV is determined by the GPS.
In a case of carrying out the autonomous flight of the UAV, a flight plan is prepared for defining the measuring range and the flying route based on the information already known such as map data or design drawing of the structures or the like. Further, by performing a flight of the UAV according to the flight plan, regarding the objects to be measured such as bridges, dams, etc., an image is obtained and a measuring is performed.
In the cases of a structure such as bridge, dam, a shape of surface is not constantly flat, and is tilted or curved, or the surface is irregular. However, the flight plan as given above is a two-dimensional flight plan based on the information based on map information and drawings, and no consideration is given on tilting, curving, or irregularity. For this reason, it is not possible to keep a distance between the structure and the UAV at a constant value.
For instance, in a case where the maintenance is performed on a structure, it is necessary to detect a micro crack of about 0.2 mm on concrete surface. A resolution of the images corresponds to the distance to a subject for photography, and in order to detect the micro crack of about 0.2 mm, it is necessary to obtain an image of the structure from a close-in distance of about 2 to 10 meters. However, in a flight plan in the past, it has not been possible to maintain a distance from the structure to the UAV at a constant value, and a photographing has been carried out at a certain predetermined distance where a collision can be avoided, and there have been the cases where it have been difficult to detect the micro crack or the like.